recv 在收到 transmitFile() 函数后没有停止

我正在使用Winsocket for class编写一个小型的服务器/客户端文件传输，它基本上可以工作，只是在我收到文件并将其写入HDD后，我无法在套接字上接收更多消息。

传输代码像这样：

    long size = GetFileSize(hFile, NULL);
TransmitFile(_socket, hFile, size, 0, NULL, NULL, TF_DISCONNECT);
ok = ::recv(_socket, cantwortfilename, 100, 0); // getting a confirmation (1)
cantwortfilename[ok] = '';
cout << cantwortfilename << endl;
char test[] = "ok!";
::send(_socket, test, strlen(test), 0); // to test if server receives again (2)

我用0而不是大小进行了尝试，结果相同。

现在到服务器端的接收：

    HANDLE hFile = CreateFile(filepathlong, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
while (1)
{
    ReadFile((HANDLE)_socket, &buffer, MAX_PATH, &dwbr, &AsyncInfo);
    GetOverlappedResult((HANDLE)_socket, &AsyncInfo, &dwbr, TRUE);
    if (dwbr == 0) break;
    WriteFile(hFile, buffer, dwbr, &dwbr, NULL);
}
char test[] = "alles ok!";
::send(_socket, test, strlen(test), 0); // sending the confirmation (1)
CloseHandle(hFile);
 i = ::recv(_socket, test, 10, 0); // receiving the test (2)
test[i] = '';
cout << "empfangen:" << test << endl;

据我所知，文件的传输工作良好(尝试rar.jpg(和

::send(_socket, test, strlen(test), 0); // sending the confirmation (1)

出去也很好。

但在那之后的接收什么都没给我？还是什么空的？我猜是空的，因为recv也没有阻止程序。但是当我把它发出去的时候，"i"将是0。

为了检查while(1(循环中的内容是否出现了某种错误，我尝试了另一种方法来接收文件。

第二次尝试：

    int r;
ofstream file(filepath, std::ios::out | std::ios::binary | std::ios::trunc);
char *memblock;
int size = 7766; // was the size of the file i was testing with
memblock = new char[size];
memset(memblock, 0, size);
if (file.is_open()){
    //while memory blocks are still being received
    while ((r = recv(_socket, memblock, 256, 0)) != 0)
    {
        //if there's a socket error, abort
        if (r == SOCKET_ERROR)
        {
            cout << "error" << endl;
        }
        //write client's file blocks to file on server
        file.write(memblock, r);
    }
    delete[] memblock;
    //finished sending memory blocks; file is completely transferred.
    file.close();
}

之后，再次发送一个具有相同结果的recv。这个文件有效，但再次收到却让我感到有些空虚。

有人能告诉我为什么以及如何解决这个问题吗？如果可能的话，尽可能少的改变？

谢谢，Martin

编辑：现在对我有效的代码：

    char csize[256];
rc = recv(_socket, csize, 256, 0);
csize[rc] = '';
int size = atoi(csize);
int bytes_read = 0, len = 0;
int r;
ofstream file(filepath, std::ios::out | std::ios::binary | std::ios::trunc);
char *memblock;
memblock = new char[size];
memset(memblock, 0, size);
if (file.is_open()){
    while (bytes_read < size){
        len = recv(_socket, memblock + bytes_read, size - bytes_read, 0);
        bytes_read += len;
    }
    file.write(memblock, size);
    delete[] memblock;
    file.close();
}